Apparatus for the fractionation of heavy oils



Aug. 23, 1932. BARBET 1,873,734

APPARATUS FOR THE FRACTIONATION OF HEAVY OILS Filed May 8. 1928 Commas! D i SEPARATOR Vacuum Q1 RECEIVER B ,PLATE COLUMN 4 COOLER VPLUUM REOTIFING b 6 3 1 F COLUMN FEEDING Rsoeuvens I v v v v v v v v v v v v v n arbae W gQi Patented Aug. 23, 1932 QUNITED STATES "PATEN OFF E EMILE noeusrm BARBET, on rams, nuance APPARATUS rota THE'IFRACTION-ATION on. HEAVY OILS Application filed-May-8,-1928,-Seria1 Noi 276,150, and. in ma -e May 12, 1927.

f It is easy to separate the volatile constituen'ts contained in hydrocarbons and particularly in crude petroleum by steam, owing "to their low boiling points, but it is 'diflicu'lt to frac'tiona'te lubricating oils the boilingpoints of which are so high that steam distillation is not possible. i r I p There'is however-the possibility of superheatin'g the steam, but itthen turns into a true gas,having a specific temperature which is low, the co-eificient' of heat exchange being unfavourable and necessitating large heating surfaces. Q

One is thereforeobliged to'heat the apparatus by direct firing, but heating under these conditions always provokes cracking, which produces deposits of. coke upon the inner side of the boiler. The necessity of stopping the fractionation for cleaning thebo ilers puts the apparatus out of action for a relatively'long period of time. I

Thezprocess and apparatus which'will'be described has for its object to avoid these ditficulties. Avacuum is employed in order to bring down the boiling points of the oilloy treated.

On the other hand, considering that it'i s mostly the heating with direct firing-which provokes cracking, it isnecessary to avoid 0. according to the kind of products freaching boiling temperature in the direct fired boilers. Letus suppose that, in a first, continuous apparatus which can beof any design, the

crude petroleum has already been deprived of itslight andheavy fractions, up to the temperature of say 160 tolZO (1, which temperature can be easily obtained by means of steam generators working at a pressure of 10. kgs. per sq. centimeter.

The: accompanying drawing does not inclnde this first apparatus, but the first column --B' is already under vacuum and is required for separating white spiritand lamp oils.

Crude petroleum free from volatile fracpart of vthe lighter products.

tions, and having a temperature of about 160 C. enters the automatic feeding'fvessel A treatment.

The vapours thus formed from the'pe'troleum ascend through the plates of the rectifymg column B. The remaining liquid flows in the usual way onto the'lowe'r plates B and passes then into the tubular heater "C, which receives the full pressure of the steam gen- 35 ,erators'by which the heating is effected.

The petroleum vapours produced by the heater ascend,o wingtothe vacuuin,throu'gh the plates B provoking the ebul'lition ofthe lighter hydrocarbons which join the other evaporated hydrocarbons and ascend together, through the plates B'reachin'g the condenser D which is effective enough to condense and to cool the distillate.

The outlet for the distillate is provided with the separation vessel (Z. At thetop of said vessel apipeconnects it with the receiver V and another pipe P connects this receiver with the vacuum pump, which is not shown on the drawing. I One portion of the liquid distillate flows into the sight glass 1 and it is white spirit; another portion isreturned through pipe line 2 to the top of the column B; two successive eXtra'ctions'are made from M the plates-fin 3 and in 4. The products of these two extractions are cooled inthe cooler E andare' sent thence to the sight glasses'5 and 6, connected with vacuum in order to permit outlet.

The extract from 3 is high grade petroleum; the extract from 4; is common petroleum i. e. containing a small quantity of heavier oil.

Every sight glass is connected with a small Vacuum vessel and the plant is equipped with the necessary number of small pumps for drawing the liquids into these three vacuum vessels and driving the fractionated products out into the storage tanks.

The central column F is similar to the column BB; and also operates under vacuum, but its purpose is to separate the products boiling at high temperatures, one cannot therefore apply steam coil heating as in the case for column BB.

The crude petroleum deprived of its lamp oils, coming from C is therefore heated in the direct fired boiler HH to a temperature below boiling but sufficient to heat it up to about 220 C.

A pump P extracts the residue from the vacuum heater C and drives it through line 00 to the top of the boiler HI-I. After warming up,- the liquid passes through the valve h and ascends by pipe pp up to the bottom of column F, where it is also instantaneously vapourized by the vacuum obtaining in column F the lighter products being vapour ized i. e. all those boiling, under normal pressure, at about 300 C. The lightest fractions will leave the column through condenser G and separator g ultimately reaching the test glass 7. The surplus of the liquid will descend through line 8 and enter the top of column F. From this column two further extractions are made at points 9 and 10, exactly in the same way as previously described for column B.

These extracts from 9 and 10 reach respectively the test glasses 12 and 13, connected with vacuum chambers.

This column will therefore give, as in column B, three fractions constituting three fractions of oil, having different properties depending upon the oil initially treated.

The liquid coming from the bottom of the column F (which contrary to the column B has neither lower exhaustion plates nor heater) pass to another direct fired boiler, which will warm it up to about 260/270 C. i. e. at least 50 C. under its boiling point at normal pressure.

Pump 1 drives the residue from the column F through the pipe line ff into the boiler KK. The product heated up leaves this boiler through valve is and ascends through line m up to the receiver L.

All that can be volatilized under influence of vacuum and of this temperature, is instantaneously vaporized, and ascends through line 1 up to the coil M.

The exit vessel of the coil is under vacuum, its upper part being connected by a tube with a vacuum vessel V.

The condensed liquid, which is an extremely dense and viscous oil, comes out through test glass 14;, connected like the .others to a vacuum vessel.

apparatus reached the final point which it h is possible to obtain from crude petroleum by distillation.

Between the boilers HH and KK the drawing represents another similar boiler .QQ, which may serve .as spare boiler either for HH or KK. The methodical warming up without boiling does not result in cracking, it could nevertheless, after a long period of time, produce some carbon deposit which ought to be eliminated. This deposit is of course very small, not only because the oils are merely warmed up, but also because of the fact that the limit of this warming is still by 50 or 60 C. lower than the boiling points these oils possess under normal pressure.

It is known that cracking takes place more readily, the higher the boiling point of the oil under treatment; this is the reason why almost every cracking process implies heating under pressure, in order to elevate this boiling point.

One spare boiler will be sufficient since cleaning has to be done very seldom.

One can easily provide piping and taps allowing, when desired, the spare boiler QQ' to be filled either with the liquid contained in HE or in KK. This decanting can be made either by pumping or by the aid of slightly compressed air.

The warming up boilers being under normal pressure, are represented in shape of two superposed cylinders in order to utilize the heat of the fires to the best advantage, but they can of course comprise a single cylinder or many cylinders in order to aid the heating throughout the mass of oil during the continuous warming up of the liquid, from its entering to its exit.

What I claim is:

Apparatus for the continuous rectification of hydrocarbons for the fractionation of heavy oils from petroleum which has been deprived of its more volatile constituents, comprising, a rectification column adapted to operate under vacuum whereby the lighter products are removed, a steam heater for said column, a heating boiler, means for passing the residuefrom said column into the heating boiler where it is heated by direct heat to a temperature below its boiling point, a second rectifying column, means for supplying the heated residue of the first rectifying column to the said second rectifying column which latter is adapted to operate under vacuum whereby lubricating oils are fractionated, a second heating boiler, means for passing the residue of the said second column into said second heating boiler Where it is heated by direct heat to a temperature below its boiling point and means for supplying the heated residue from said second heating boiler to a vacuum vessel, whereby further fractionation takes place leaving a residue of mazout.

y In testimony whereof I have signed my name to this specification.

EMILE AUGUSTIN BARBET. 

